Automatic casting having sprue-removing means

ABSTRACT

An automatic casting machine is equipped with a transfer rod having a tip adapted to be inserted in the sprue of a casting while the sprue is still molten. The mold is then opened, the casting lifted out of the mold by the transfer rod, the tip of which is now fast to the sprue, and transferred to a work table at which the transfer rod, sprue and casting separated from each other.

United States Patent Marcel Thevenin Rue de lAvenir, Champagnole Juea,France Appl. No; 792,986

Filed Jan. 22, 1969 Inventor Patented Feb. 16, 1971 Priority Jan. 25,1968 France 137,449

AUTOMATIC CASTING HAVING SPRUE- REMOVING MEANS 4 Claims, 4 Drawing Figs.

Int. C1 822d 29/00 Field of Search 164/404, 344, 269, 345, 344,131, 132,69, 70,334; 249/66,68, 63

[56] References Cited UNITED STATES PATENTS 1,088,233 2/1914 Loesser249/68 1,387,290 8/1921 Morse r 164/132 1,458,343 6/1923 Kelm 249/632,000,449 5/1935 Kistinger 249/63X 2,043,252 6/1936 Kronbach.. 249/63X2,917,798 12/1959 Ross 22/200 1,128,251 2/1915 Holton 164/69 Pri r 1 t1[y Eramingr- Charles W. Lanham Assistant Examiner-V. K RisingAttorney-Holcombe, Wetheri11& Brisebois ABSTRACT: An automatic castingmachine is equipped with a transfer rod having a tip adapted to beinserted in the sprue of a casting while the sprue is still molten. Themold is then opened, the casting lifted out of the moid by the transferrod, the tip of which is now fast to the sprue, and transferred to awork table at which the transfer rod, sprue and casting separated fromeach other.

PATENTEU FEB 1 6 I97! SHEET 1 OF 2 AUTOMATIC CASTING HAVINGSPRUE-REMOVING MEANS SUMMARY OF THE INVENTION This invention relates toa foundry for casting metal, especially light alloys. Its object is toprovide not only means for automatically carrying out the operations ofclosing the mold, pouring in the metaL stopping the pouring, andejecting the castings, but also for carrying out all the subsequentoperations of transferring the casting, and removal of the sprue fromthe casting, which steps are ordinarily carried out by hand by theworkmen.

It is an object of the present invention to provide, as a new article ofmanufacture, a metal-casting machine essentially characterized by thefact that it comprises in combination a crucible provided with heatingmeans for keeping the metal therein molten and a lower outlet from whichthe metal may be poured, said outlet being controlled by electricalmeans, a metallic mold equipped with conventional opening, closing,locking and ejecting means, mounted on a carriage, said mold beingequipped with electrodes connected in the electric circuit whichcontrols the outlet, a table on which the carriage is driven underappropriate control between a first position in which the tap hole ofthe mold is located beneath the outlet of the crucible, and a secondposition in which said tap hole is accessible from the top, and a longtransfer rod vertically positi gabove the tap hole in its secondposition. Thelower end .1; i

transfer rod ends in a cylindrical or slightly conical finger, while itsupper end is supported by a hydraulic cylinder capable of moving thetransfer rod axially to introduce the finger into the sprue of thecasting before that sprue solidifies. This hydraulic cylinder is mountedto be swung about a horizontal axis by a transverse hydraulic cylinderadapted to bring the finger and the sprue of the casting, afterretraction and extension of the rod, to a station at which the sprue isseparated, and at which a hydraulic cylinder holds the sprue whileanother hydraulic cylinder assists the longitudinal hydraulic cylinderin the extraction of the finger from the sprue, and at which suitablemeans separates the sprue from the casting by breaking, cutting orsawing it. The hydraulic cylinder holding the sprue then releases itsgrip and the sprue falls into a container designed to receive it.

In order that the object of the invention may be better understood,onerepresentative embodiment thereof will now be described, purely by wayof illustration and example, with reference to the accompanyingdrawings, in which:

FIG. I is a schematic elevational view, partially in section, showingthe equipment according to the invention;

FIG. 2 is a sectional view, taken along the line II-II of FIG.

FIG. 3 is a sectional view on a larger scale taken through the mold inits closed position; and

FIG. 4 is a view similar to FIG. 3, but showing the mold open.

The installation comprises a crucible 1 inside a furnace 2 andcontaining the molten metal 3, usually a light alloy. The lower part ofthe crucible is provided with an outlet 4, normally closed by thepointed lower end of a rod 5, the upper end ofwhich is controlled by anelectromagnet 6.

Under the furnace 2 is a casting table 7 on which a carriage 9 travels.This carriage is actuated by a hydraulic cylinder 8 and carries thefixed part 10 of the mold, which is equipped with ejectors II controlledby a hydraulic cylinder 12, and the movable part I3 of the mold, whichis controlled by the hydraulic cylinder 14.

In the course of its movements the carriage may take either of twoextreme positions defined by the stops I5 and 16 or by contacts at theends of the path of travel. The first of these positions, shown inbroken lines on FIG. 1, is so determined that the top gate 17 of themold is directly under the crucible outlet 4. In the upper part of thetop gate 17 are two electrodes 18 which are insulated from the metallicbody of the mold and connected to an electrical circuit which determinesthe exact moment at which the molten metal reaches the level of theelectrodes. A manual or automatic control energizes the electromagnet 6which causes the molten metal to flow out of the mold, and, when thedesired level is attained, closes the circuit between the electrodes 18which opens the circuit of the electromagnet 6 to discontinue pouring,by means of a cutoff relay connected to said electrodes The hydraulicjack 8 then moves thecarriage into its second position, shown in brokenlines on FIG. 1. In this position, and

before the heart of the liquid metal in the top gate which is to becomethe sprue 19 has had time to solidify, a finger 20 at the end of avertical transfer rod 21 is introduced into the tap hole. The metal thencompletes its cooling, thus fastening the sprue to the finger 20.

The transfer rod 21 is moved longitudinally by a longitudinal jack 22connected to the upper part of this rod and preferably consisting of acompressed air cylinder which is hydraulically cushioned at the end ofits stroke to prevent the finger from being too abruptly introduced.This transfer rod 21 preferably comprises a cooling jacket supplied withwater through flexible tubes 23.

It is also adapted to move angularly about its upper end, as shown inbroken lines on FIG. I. For this purpose the base of the jack 22 ispivotally attached to a stationary member at 24 and to a lateral jackwhich is adapted to swing the jack 22 about the pivot point 24. In orderto avoid bending of the rod '21 in the case of inopportune jamming, thejack 25 preferably acts on the jack 22 through a fork 26 in thedirection indicated by the arrow 27, whereas the jack 22 is biassed inthe opposite direction by a return spring 28, when the fork iswithdrawn. The rod 21 is. guided during these movements by two flatplates 29, and is exactly centered at each of its extreme positions inV-shaped stops 30, as shown in FIG. 2.

After the part 13 of the mold is opened by the jack 14, as shown in FIG.4, and after the extractors 11 have been actuated by the jack 12, asshown in broken lines on the same figure, the above-describedarrangement makes it possible for the transfer rod to be retracted bythe jack 22 in the direction indicated by the. arrow 31 in FIG. 4. Thislongitudinal displacement of the rod 2] draws with it the finger, thesprue I9, and the casting 32 which follows it. The actuation of the jack25 then moves the assembly to the right of FIG. 1, and, after the rod 21is again moved in the direction of the arrow 33 by the jack 22, theassembly comprising the casting 32 and sprue 19 comes to rest on afinishing table 34 which is inclined to allow for the swinging motionofthe rod 21.

Above this table is a jack 35 which actuates a jaw 36 which clamps thesprue 19 against the table 34. A supplemental device then separates thecasting 32 from the sprue. This device may comprise a second jack 37which exerts pressure on the casting and simply breaks the sprue off atthe narrow neck by which the sprue is connected to the casting. It isalso possible to use a trimming press, or cutting means utilizing a saw,a milling tool, or a grinding wheel. In any case the sprue, and thus thecasting, is brought into a precise position in which it is heldstationary, and in which it may be recentered in an appropriate mold. Itis thus easy to control the abovedescribed devices to carry out thecutting operation with precision.

At the same time that the sprue is removed from the casting, a seconddevice extracts the finger 20 from the sprue. In effect, the forcenecessary to longitudinally extract this linger is generally greaterthan the jack 22 is capable of exerting. It is thus necessary, for ashort time at the beginning ofthe retracting movement, to exert agreater force on the transfer rod 21. This may be done by utilizing anadditional jack 38 which acts on a lever 39 pivotally mounted at 40 on astationary member and ending in a fork 41 which acts on two projections42 on opposite sides of the rod 21. After this extraction, the rod 21,still in retracted position, returns to the position shown in solidlines on FIG. 1, ready to pick up the next casting. The jack 35 thenreleases the sprue 19 which falls into a container 43,

while another container receives the casting, as hereinbefore described.

It will thus be seen that it is possible to produce a large quantity ofcastings without requiring any manual stop other than the charging ofthe furnace and the emptying of the containers 43 and 44. All theoperations, which consist in energizing the electromagnet 6 and thevarious jacks may easily be controlled in an automatic or semiautomaticcycle, although in the former case stop means at the ends of the pathsof travel should be provided as a safety precaution.

The finger 20, as has been seen, is a piece of steel which is slightlyconical in shape so as to permit the sprue to be firmly attachedthereto, while avoiding subsequent difficulty in its extraction.Depending on the castings, the sizes of the sprues and the alloys used,the optimum angle may vary and the finger may even become cylindrical,and possibly comprise several sections of different diameters, but it isclear that one finger may serve for many very different types ofcastings so that the equipment may quickly be adapted to manufacture anynumber ofdifferent types of castings by simple adjustment after, ofcourse, changing the mold. For heavy castings it is possible to useseveral fingers by providing several inlets in the mold for theformation of sprues, in each ofwhich a finger may be seated.

In addition to the advantages of being completely automatic and easy toadapt, the machine according to the invention has the advantage that theintroduction of the finger 20 into the sprue just before it hardensimproves the quality ofthe casting by accelerating the cooling of thesprue and placing the metal under a little pressure, which avoids theflaws which are often produced in the neck between the sprue and thecasting. It is also obvious that the same furnace 2 may receive twocrucibles 3 which are symmetrically positioned and which use the sametable, equipped with duplicate gripping and cutting devices.

It will of course be appreciated that the above embodiment has beendescribed purely by way of illustration and example and may be modifiedas to detail without thereby departing from the basic principles of theinvention.

In particular, the casting may be air or water cooled to facilitateremoval of the sprue. On the other hand, the containers for receivingthe castings may be replaced by conveyors which carry the castings tofinishing stations.

I claim:

1. In a casting'machine comprising a crucible, a mold having a top gate,and a work station, the improved handling means which comprises atransfer rod having a lower end dimensioned to lie within said top gatewhile leaving sufficient room therein to permit the formation ofa spruetherearound, means for vertically translating said transfer rod to lifta casting attached to said sprue from said mold, means for swinging saidtransfer rod from a position above said mold to one in which saidcasting is supported at said work station, and means for separating saidtransfer rod, sprue, and casting from each other.

2. A casting machine as claimed in claim 1, in which said handling meanscomprises fluid pressure actuated means for gripping said separating atsaid work station so that said transfer rod may be separated therefrom.

3. A casting machine as claimed in claim 1, in which said separatingmeans comprises means for striking said casting while said sprue is heldby said gripping means, so as to break said casting away from saidsprue.

4. A casting machine as claimed in claim 1, in which said mold ismounted to slide between a first position in which its top gate isbeneath the pouring hole of said crucible and a second position beneaththe lower end of said transfer rod.

1. In a casting machine comprising a crucible, a mold having a top gate,and a work station, the improved Handling means which comprises atransfer rod having a lower end dimensioned to lie within said top gatewhile leaving sufficient room therein to permit the formation of a spruetherearound, means for vertically translating said transfer rod to lifta casting attached to said sprue from said mold, means for swinging saidtransfer rod from a position above said mold to one in which saidcasting is supported at said work station, and means for separating saidtransfer rod, sprue, and casting from each other.
 2. A casting machineas claimed in claim 1, in which said handling means comprises fluidpressure actuated means for gripping said separating at said workstation so that said transfer rod may be separated therefrom.
 3. Acasting machine as claimed in claim 1, in which said separating meanscomprises means for striking said casting while said sprue is held bysaid gripping means, so as to break said casting away from said sprue.4. A casting machine as claimed in claim 1, in which said mold ismounted to slide between a first position in which its top gate isbeneath the pouring hole of said crucible and a second position beneaththe lower end of said transfer rod.